Directions:Heat oven to 375. Peel and slice celeriac into 1/8 inch pieces. Simmer in water over medium heat until just tender, 15-20 minutes. Drain. In medium saucepan, melt butter, add flour and cook until golden. Remove from heat and slowly whisk in stock. Heat again until boiling. Cook until thick and season with salt and pepper. Placed drained celeriac in a shallow 8-inch baking dish and pour sauce over the celeriac. Sprinkle with cheese and bake until golden brown about 15 minutes. Serves 4-6.